Patent GB-220799-A (GB)
Title: Improvements in automatic typewriters
IPC: B41J5/38
Filed: 1923-08-10
Abstract: 220,799. Vox Maschinen Akt.-Ges., and Vogelsang, W. Aug. 10, 1923. Strip-controlled driving-mechanism; pneumatic driving-mechanism; type-wheel machines.-Relates to machines of the kind in which complete lines of types are set on a series of type-carriers, and consists in the provision of means whereby the type-carriers are set by periodical movements of different extent. The apertures of the strip are arranged in longitudinal rows I - - VI, Fig. 1, and grouped transversely, the different groups of apertures controlling separate type-carriers through pneumatic, electrical, or mechanical means. To each longitudinal row of apertures is assigned a certain numerical value, and the added value of a transverse group is equal to the numerical position occupied by a type sign in a range of such signs. In the example, shown in Fig. 1, the value of the rows are in geometrical progression, with a constant ratio of 2. Fig. 4 shows one of a line of type-wheels 18, the simultaneous setting of which is effected through pneumatically operated pistons 12 which are actuated periodically when an aperture in the travelling strip comes into alignment with an air admission port. The type-wheels are frictionally clutched to a continuously rotating shaft 31, and are normally held stationary by slidable detents 17. A hooked bar 13 projecting through an aperture in the detent 17 is pivotally connected to the piston 12 by a link 20. and the vertical movement of the bar 13 is controlled by a spring 72 and a link 71 pivoted to the machine frame at 70. A doublearmed lever 14 with hooked ends is pivoted above each bar 13 and rocked bv a continuously rotating cam wheel 15 provided with cam ridges I - - VI. which extend around the circumference for distances proportional to the numerical values assigned to the aperture rows of the strip. When the hooked bar 13 is raised by the piston 12, its hooked upper end is engaged by the hook at the end of the rocking-arm 14 above, it, and the detent 17 slides to release the type-wheel, which then rotates. The bars 13 are released and allowed to drop each time the two-armed lever 14 leaves a cam ridge, the air pressure to the piston being relieved in the meantime. Where a character is represented by several apertures grouped transversely in the strip, the type-wheel moves a corresponding number of times for each setting. After the printing of a line, the typewheels are restored to their original position by a cam 30 engaging one end of a pivoted forked lever 29, the other end of which is in engagement with the end of the sliding detent 17, thereby withdrawing the latter and allowing the type-wheel to rotate until a specially long ratchet tooth 33<1> engages the detent 17, as shown in Fig. 4. Type-bar machines.-The application of the invention to type-bar machines is shown in Fig. 5. The type-bars 38 are formed on their undersides with racks which are engaged by pinions 39 frictionally clutched to a continuously rotating shaft 40. The movement of the type-bars is normally restrained by the detents 17 through which pass the slidable bars 13 pivotally connected to the pistons 12. The two-armed levers 14, rocked by the cam ridges on the continuously rotating cams 15, engage the hooked ends of the bars 13 when the latter are projected by the pistons 12, thereby withdrawing the detents 17 from engagement with the racks, and allowing the pinions to move the type-bars forward. The type-bars are returned to their original position after each setting bv an automatic reversal of the piniondriving shaft 40. In a modification, shown in Fig. 6. a slide 55<1> arranged beneath the typebars 64 is moved forward periodically by an endless chain 55. Pawls 60 pivoted upon the slides 55<1> are provided with studs 61 which are engaged by links 62 to put the pawls into engagement with the toothed type-bars when the pistons 63 are projected. The endless chain 55 passes around two guide rollers 56, 57 and is moved forward when a lever 53 ra.ises guiderollers 54 to put the chain into engagement with a continuously rotating toothed wheel 52. The lever 53 is controlled by cam ridges on a continuously rotating cam 15. The chain 55 moves forward against the tension of a spring 58, retrograde movement being prevented by a spring- controlled detent 59<1>, which is disengaged after the printing by means of a stud 65 on the cam 15. The type-bars are returned with the slides 55<1>, by engagement of the pawls 60 with shoulders 66 at the ends of the type-bars. Hammer-impression arrangements; line-spacing mechanism.-Spring-supported hammers 26, Fig. 4, are mounted in frames 21<1> which are pivoted at 16 and forced backwards against the tension of springs 23 by rotating cams 22 which bears against studs 21 on the frames. The hammer is projected when the stud drops into a notch in the cam, and is retracted by a spring 25 secured to the support for the frame 21. The paper 24 passes between rollers and between the type-wheels and impression-hammers. A ratchet wheel 28 on the feed roller is engaged by a spring 27 and rotates the roller for line spacing each time the frame 21<1> is rocked. Type-wheels.-The type-wheel shown in Fig. 9 consists of a disc 33 with ratchet teeth around its periphery, and an annular type-holder 35 into which the stems of the types 36 are loosely inserted. A wire ring threaded through the inner ends of the stems secures them in position. The discs 33 are arranged loosely on the continuously rotating shaft 31, between smaller discs 32 which are keyed to the shaft. and rotate with it. A resilient membrane 34 clamps the loose disc 33 between the fast discs 32 with sufficient pressure to cause them to rotate together when released by the detent 17, Fig. 4.